Write the conversation response. 
 * What is meant by Hormone receptor positive breast tumor?;
 * Hormone receptor positive breast tumor A hormone-receptor-positive (HR+) tumor is a tumor which consists of cells that express receptors for certain hormones.;
 * What types of hormones?;
 * The term most commonly refers to estrogen receptor positive tumors (i.e. tumors that contain estrogen receptor positive cells), but can also include progesterone receptor positive tumors.;
 * Are there any other interesting aspects about this article?;
 * 
Estrogen-receptor-positive tumors depend on the presence of estrogen for ongoing proliferation.